M509 


Ube  Ylbtamt  Bulletin 


SERIES  VIII 


DECEMBER,  1909  Number  6 


OHIO  STATE  NORMAL  COLLEGE 
PUBLICATIONS 
TEACHERS’  BULLETIN  No.  1 1 


The  Soil  and 
Its  Relation  to  Plants 

B.  M.  DAVIS 


Published  Monthly  by  Miami  University 

And  entered  at  Postoffice ,  Oxford ,  Ohio ,  as  Second  Class  Mail  Matter 


SECOND  EDITION. 


The  first  edition  of  Teachers’  Bulletin,  No.  1,  of  the  De¬ 
partment  of  Agricultural  Education  of  the  Ohio  State  Normal 
College,  Miami  University,  Oxford,  Ohio,  published  in  May, 
1907,  was  soon  exhausted.  The  large  number  of  requests  for 
copies  and  the  many  encouraging  letters  from  teachers  who 
have  used  the  bulletin  seem  to  justify  a  second  edition  which 
is  now  presented  in  its  revised  form. 


F.  L-.  sr  I e.5 


THE  PLACE  OF  AGRICULTURE  IN  PUBLIC 
SCHOOLS. 


During  the  last  few  years  there  has  been  earnest  discus¬ 
sion  as  to  the  desirability  of  having  instruction  given  in  our 
elementary  schools,  particularly  in  those  of  rural  communities, 
involving  some  of  the  fundamental  principles  of  agriculture. 
It  is  now  generally  admitted  that  such  instruction  is  desirable, 
and  the  general  attitude  of  those  interested  in  education  is  fav¬ 
orable  toward  it.  (18,  19)* 

In  Ohio  and  other  places,  where  the  subject  is  not  re¬ 
quired  to  be  taught,  there  is  some  hesitancy  on  the  part  of  the 
teachers  toward  introducing  it  into  their  schools.  Although 
they  may  believe  in  it,  the  teachers  do  not  see  quite  clearly 
how  to  find  a  place  for  it.  Furthermore,  they  do  not  know 
just  how  to  make  a  start,  for  it  is  a  new  and  unfamiliar  sub¬ 
ject.  Not  being  able  to  find  a  place  for  it  is  not  'a  valid  objec¬ 
tion.  Although  the  course  of  study  may  appear  to  be  over¬ 
crowded,  much  time  and  efficiency  would  be  gained  by  atten¬ 
tion  to  two  important  particulars  which  are  now  lacking  for 
the  most  part  in  most  schools,  viz. :  (1)  practical  application 

of  the  formal  subjects;  (2)  forms  of  school  activity  other  than 
the  formal  preparation  and  recitation  of  lessons  from  text¬ 
books.  Some  subject  is  needed  which  involves  in  a  concrete 
way  some  practical  use  of  arithmetic,  written  language,  and 
reading.  Hypothetical  problems,  many  of  them  having  only  the 
remotest  application  to  the  life  the  pupil  will  lead,  essays  using 
sentences  which  are  empty  of  all  thought,  reading  which  is  but 
the  mechanical  calling  of  words,  these  are  faults  which  have 
inevitably  crept  into  our  schools,  and  which  every  true  teacher 
deplores  and  tries  to  correct. 

Certain  phases  of  elementary  agriculture  deal  with  com¬ 
mon  and  familiar  facts  which  should  have  meaning  and  sig¬ 
nificance  to  every  country  child.  But  the  very  handling  of 

*  Figures  refer  to  references  on  pp.  32-33. 


3 


these  familiar  facts  in  such  a  way  as  to  reveal  their  meaning 
involves  the  use  of  the  formal  studies  as  tools. 

Thus  elementary  agriculture  should  have  a  place  in  the 
country  school  in  order  to.  secure  the  best  and  most  practical 
results  from  the  subjects  already  being  taught  there,  and  also 
in  order  to  secure  the  best  reaction  of  the  school  on  the 
community. 

But  the  subject  has  a  great  importance  of  its  own  which 
is  considered  by  many  sufficient  to  justify  its  introduction. 
This  point  of  view  is  seen  from  the  following  aims  of  the  sub¬ 
ject  as  set  forth  in  the  manuals  of  the  elementary  course  of 
study  of  two  of  our  most  progressive  agricultural  States : 

“1.  To  cultivate  an  interest  in  and  instill  a  love  and  re¬ 
spect  for  land  and  the  ocupation  of  agriculture. 

2.  To  create  a  regard  for  industry  in  general  and  an  ap¬ 
preciation  of  the  material  side  of  the  affairs  of  a 
highly  civilized  people. 

3.  To  cultivate  the  active  and  creative  instincts  ‘as  dis¬ 
tinct  from  the  reflective  and  receptive  that  are  other¬ 
wise  almost  exclusively  exercised  in  our  schools. 

4.  To  give  practice  in  failure  and  success,  thus  putting 
to  the  test  early  in  life  the  ability  to  do  a  definite  thing. 

5.  To  train  the  student  in  ways  and  methods  of  acquir¬ 
ing  information  for  himself  and  incidentally  to  ac¬ 
quaint  him  with  the  manner  in  which  information  is 
originally  acquired  and  the  world’s  stock  of  knowledge 
has  been  accumulated. 

6.  To  connect  the  school  with  real  life  and  make  the 
value  and  need  of  schooling  the  more  apparent. 

7.  As  an  avenue  of  communication  between  the  pupil 
and  the  teacher;  it  being  a  field  in  which  the  pupil 
will  likely  have  a  larger  bulk  of  information  than  the 
teacher,  but  in  which  the  training  of  the  teacher  can 
help  to  more  exact  knowledge.” 

(Course  of  Study  for  the  Common  Schools  of  Illinois,  1907,  pp.  207-208.) 

“The  stress  which  is  being  placed  upon  the  practical  in 
education  is  indicative  of  a  new  attitude  toward  education  in 
general.  Instead  of  emphasizing  the  knowledge  side  of  edu- 


4 


cation  we  begin  to  recognize  the  fact  that  what  a  man  is  and 
what  he  can  do  are  more  important  than  what  he  knows. 

By  making  scientific  nature  study  and  agriculture  a  part 
of  the  curriculum,  habits  of  scientific  thinking  may  be  ac¬ 
quired,  a  love  of  nature  developed,  and  the  practical  work  will 
make  the  student  a  more  useful  member  of  society.  If  we 
admit  that  education  should  aid  in  preparing  the  child  for  life, 
we  readily  see  how  necessary  it  is  that  the  child’s  training  be 
of  such  a  character  as  to  adapt  him  to  his  environment.” 

(State  Manual  and  Uniform  Course  of  Study  for  Elementary  aud  Secondary  Schools 
of  Indiana,  1909,  p.  107.) 

PURPOSE  OF  BULLETIN. 

Most  of  the  exercises  outlined  in  this  bulletion  represent 
work  that  has  actually  been  done  by  pupils  of  the  sixth  to 
eighth  grades.  Part  of  the  work  was  done  by  pupils  of  the 
Country  Model  School  No.  1,  Ohio  State  Normal  College,  an 
ungraded  district  school  enrolling  about  twenty-five  pupils,  in 
Oxford  Township,  Butler  County,  Ohio. 

The  bulletin  is  intended  to  encourage  and  assist  teachers 
who  wish  to  introduce  elementary  agriculture  into  their 
schools  and  do  not  know  just  how  to  begin  or  how  to  con¬ 
duct  the  instruction. 

The  subject  of  the  soil  and  its  relation  to  plants  is  taken 
up  partly  on  account  of  its  fundamental  importance  in  farm 
practice,  and  partly  because  it  represents  fewer  difficulties  in 
the  way  of  experimental  study  to  be  carried  on  by  pupils  of 
the  grades  or  of  the  first  year  of  high  school.  Furthermore, 
it  is  one  of  the  few  phases  of  the  subject  of  agriculture  that 
may  be  studied  to  advantage  during  the  winter.  Indeed,  ex¬ 
perience  has  shown  that  such  work  as  suggested  in  the  fol¬ 
lowing  exercises  offers  a  practical  solution  for  the  problem  of 
school  management  during  bad  weather. 

SUGGESTIONS  TO  TEACHERS  AS  TO  METHOD. 

The  following  exercises  present  concretely,  in  the  form  of 
simple  experiments,  fundamental  facts  concerning  the  soil  and 
its  relation  to  plants.  Each  exercise  helps  to  give  meaning, 
directly  or  indirectly,  to  some  essential  of  plant  growth.  Many 


5 


of  them  will  at  once  suggest  reasons  for  some  of  the  most 
common  practices  in  successful  farming. 

The  account  of  the  plant  and  its  work  (pp.  6-8  and  Fig.  )) 
is  intended  to  give  the  teacher  a  short  but  general  perspective  of 
the  plant  in  all  its  relations.  Most  of  the  exercises  are  intro¬ 
duced  by  a  brief  note  of  explanation.  An  account  is  then 
given  as  to  how  the  experiment  or  demonstration  should  be 
conducted  and  attention  is  called  to  the  points  to  be  observed. 
Under  Application,  is  mentioned  familiar  facts  or  practices 
which  the  observed  results  help  to  explain. 

Each  subject  should  be  presented  to  the  pupil  as  a  prob¬ 
lem.  The  nature  of  the  problem  is  suggested  in  the  title  of  the 
exercise,  and  its  connection  with  previous  work,  or  with  other 
problems  is  indicated  by  the  explanation.  Suggestions  should 
be  made  to  the  pupils  as  to  how  to  proceed  to  get  an  answer 
to  the  problem.  It  is  important  for  each  pupil  to  do  every¬ 
thing  he  can  for  himself.  For  example,  the  rack  in  Exercise 
XI  (Fig.  3)  was  made  by  the  pupils  of  the  model  district 
school  No.  1,  and  the  apparatus  was  set  up  by  them. 

The  few  pieces  of  simple  and  inexpensive  apparatus  may 
be  provided  at  the  beginning  of  the  course.  The  reference 
books  and  pamphlets  should  also  be  secured  at  this  time.  The 
pupils  should  be  encouraged  to  write  for  and  thus  obtain  the 
government  and  state  publications  for  themselves.  If  the  en¬ 
tire  list  of  apparatus  or  references  can  not  be  afforded,  get 
what  seems  to  be  the  most  important.  But  much  of  the  work 
may  be  done  without  any  expense  whatever. 

If,  for  any  reason,  the  entire  series  of  exercises  can  not 
be  undertaken,  the  teacher  is  advised  to  have  the  pupils  try  a 
few,  so  as  to  make  a  beginning. 

Finally,  the  writer  will  gladly  reply  to  inquiries  from 
teachers  concerning  any  points  in  the  bulletin  not  clearly  un¬ 
derstood. 


THE  PLANT  AND  ITS  WORK. 

Any  intelligent  effort  to  grow  plants  must,  first  of  all, 
take  into  consideration  the  needs  of  the  plant.  In  order  to 
understand  these  needs,  the  work  of  the  plant  in  all  of  its  most 


6 


t 


important  relations  to  sunshine,  air,  soil,  and  water  must  be 
known. 

For  the  plant  to  live  and  thrive  it  must  have  sunshine, 
oxygen,  food,  and  protection  from  its  enemies.  The  problem 
of  plant-rearing  is  to  provide  these  essentials  for  its  growth. 

The  animal  must  rely  on  food  already  elaborated  into 
complex  compounds,  such  as  proteids,  starch-like  substances, 
and  fats.  The  plant,  on  the  other  hand,  by  using  the  energy 
of  the  sun,  is  able  to  make  these  substances  for  itself  from  the 
raw  materials  such  as  carbon  dioxid,  water,  and  mineral  salts. 

The  work  of  the  plant  is  divided  among  the  plant  organs : 
leaves,  stem,  and  roots.  The  leaves  make  most  of  the  food ; 
the  stem  supports  the  leaves  and  carries  material  to  and  from 
the  leaves ;  the  roots  hold  the  plant  in  place,  absorb  water  and 
the  mineral  salts  dissolved  in  the  water,  and  receive  in  return 
food  from  the  leaves. 

Water  exists  in  the  soil  in  thin  films  around  the  soil  par¬ 
ticles  ;  that  is,  apparently  dry  soil  may  contain  enough  water 
in  this  state  to  support  a  plant.  A  special  set  of  organs  for 
removing  water  from  these  surface  films  is  found  on  all  the 
smaller  rootlets  of  the  plant.  These  organs  are  called  root- 
hairs. 

So  far  as  supplying  the  plant’s  needs  is  concerned,  the 
most  important  part  of  the  problem  is  to  secure  proper  soil 
relations  for  the  root.  In  most  cases  if  the  plant  is  not  shaded 
the  proper  light  relation  is  secured  without  further  attention. 
There  are,  however,  special  cases  where  the  leaf  exposure  of 
larger  plants  needs  to  be  modified  by  pruning,  or  where  deli¬ 
cate  plants  need  to  be  protected  from  too  strong  sunlight  by 
partial  shade. 

Securing  proper  soil  relations  for  the  roots  of  the  plant 
being  the  chief  problem  in  plant-rearing,  it  will  be  necessary 
to  notice  what  this  means.  The  most  important  factors  are 
as  follows : 

The  soil  must  contain  sufficient  mineral  salts  for  the 
plant's  use.  The  most  important  of  these  are  the  ones  con¬ 
taining  nitrogen,  phosphorous,  and  potash.  The  use  of  ferti¬ 
lizers  is  intended  to  supply  these  salts  where  they  are  not  in 
sufficient  quantities  in  the  soil. 


7 


There  must  be  plenty  of  water  accessible  to  the  roots  in 
the  form  of  films  around  the  soil  particles.  The  amount  of 
water  which  a  given  area  of  soil  will  hold  depends  upon  the 
surface  extent  of  these  particles.  The  extent  of  this  surface, 
in  turn,  depends  upon  the  size  or  state  of  division  of  these 
particles — the  more  finely  divided,  the  more  surface,  and  con¬ 
sequently  the  greater  water-holding  capacity.  Too  finely 


Diagram  of  a  plant  showing  its  most  Important  relations:  sunlight, 
moisture,  oxygen,  and  soil. 


8 


divided  soil  particles,  however,  will  not  leave  enough  space 
for  oxygen  to  supply  the  roots ;  for  roots,  like  all  other  parts 
of  the  plant,  must  have  a  constant  supply  of  oxygen.  Too 
much  water  also  will  cut  off  the  oxygen  supply  from  the  root. 
The  soil  in  this  condition  is  said  to  be  “water-logged.”  The 
living  plant  in  its  various  relatons  may  be  seen  more  clearly 
by  a  study  of  Fig.  1.  The  directions  of  movements  of  the  vari¬ 
ous  substances  in  the  plant,  and  to  and  from  the  plant  are 
indicated  by  arrows. 

EXPERIMENTAL  STUDIES  OF  THE  SOIL  AND  ITS 
RELATION  TO  PLANTS. 

I.  The  Root  System  of  a  Plant. 

Explanation : 

By  root  system  is  meant  the  entire  group  of  the  roots 
of  a  plant.  Root  systems  are  of  two  kinds : 

(a)  Tap-root:  central  main  root  with  smaller  roots 
radiating  from  it. 

(b)  Fibrous:  many  roots  of  nearly  the  same  size.  (Fig. 

(b)  Fibrous:  many  roots  of  nearly  the  same  size. 

Roots  of  either  of  these  may  be  modified,  as  for  ex- 
which  is  a  modified  tap-root,  and  by  the  sweet  potato, 
which  is  a  modified  fibrous  root. 

Demonstration : 

(a)  Dig  up  a  clover  plant  and  remove  the  soil  from  it. 
Observe  that  it  has  a  strong  central  root  which  joins  the 
stem.  Note  arrangement  and  extent  of  smaller  roots 
which  are  connected  with  this  main  root. 

(b)  Dig  up  a  single  grass  plant  (wheat  will  do)  with 
as  many  of  its  roots  as  possible  and  remove  the  soil  from 
them.  Observe  that  the  root  system  is  composed  of  many 
roots  about  the  same  size.  They  project  from  the  conical 
portion  of  the  stem  of  the  plant  just  below  or  at  the  sur¬ 
face  of  the  ground. 

(c)  Dig  up  a  number  of  common  plants.  Determine 
which  have  tap-roots,  and  which  have  fibrous  roots.  Make 
a  list  of  common  plants  classified  as  to  character  of  their 
root  systems. 


9 


II.  Extent  of  the  Root  System  of  a  Plant. 

Explanation : 

In  the  preceding  exercise  the  root  systems  of  a  number 
of  different  kinds  of  plants  were  examined.  The  funda¬ 
mental  fact  common  to  both  types  of  root  systems  is  the 
provision  made  for  root  surface  (p.  8).  The  importance 
of  root  surface  cannot  be  too  strongly  emphasized.  The 
amount  of  food  material  brought  to  the  plant  by  the  roots 
must  vary  according  to  the  extent  of  these  roots ;  the 
greater  the  total  root  surface  the  greater  the  absorbing 
capacity.  An  interesting  problem  in  this  connection 
would  be  to  find  out  under  what  circumstances  this  ob¬ 
ject  is  best  secured  by  tap-roots  and  by  fibrous  roots. 

Determination  of  root  surface  or  extent: 

The  amount  of  root  surface  of  a  plant  may  be  roughly 
determined  by  measuring  the  roots  and  finding  their  total 
length. 

Select  some  plant  (a  corn  plant  will  do)  which  is  grow¬ 
ing  by  itself.  Carefully  dig  a  trench  around  the  plant  to 
a  depth  of  twelve  or  fifteen  inches.  The  central  ball  or 
cylinder  of  earth  will  contain  most  of  the  roots.  Remove 
by  digging  as  much  of  the  soil  from  the  roots  as  possible 
and  remove  the  rest  by  washing.  Before  removing  the 
plant  note  direction  of  growth,  whether  branched  or  not, 
in  what  part  of  soil  most  numerous,  how  near  the  sur¬ 
face  the  roots  come.  All  these  observations  should  be  put 
together  in  a  sort  of  diagram. 

Remove  the  plant,  saving  all  the  roots.  Measure  each 
one  and  find  total  length  of  all  the  roots. 

Note:  With  the  best  of  care  it  will  be  impossible  to 
remove  all  the  roots.  The  real  extent  will  be  much  larger 
than  the  calculated  amount.  The  total  length  of  all  the 
roots  of  a  well  developed  corn  plant  has  been  estimated  to 
be  over  1,000  feet ;  the  total  length  of  all  the  roots  of  a 
mature  squash  vine  has  been  found  to  be  about  15  miles. 
(1,  pp.  207-217;  3,  pp.  9-22;  16.) 

Application : 

While  the  object  of  this  exercise  is  to  furnish  a  con- 


IO 


crete  illustration  of  the  great  extent  of  the  roots  of  a  plant 
in  soil,  and  furnish  a  basis  of  appreciation  of  the  relation 
of  the  root  to  the  soil,  it  has  an  obvious  practical  lesson. 

Methods  of  cultivation  should  take  into  account  the  fact 
that  many  of  the  roots,  especially  late  in  the  growing  sea¬ 
son,  are  near  the  surface.  Deep  cultivation  will  destroy 
all  such  roots  and  to  that  extent  cut  off  the  food  supply 
of  the  plant,  thereby  lessening  the  yield  of  the  crop.  (12, 
p.  4.) 

III.  Root-Hairs. 

Explanation : 

The  root-hairs  are  the  absorbing  organs  of  a  plant,  i.  e., 
they  transfer  the  water  and  the  substances  dissolved  in  it 
from  the  soil  to  the  rootlet.  (Fig.  1.) 

Demonstration : 

Put  some  seeds  (radish  or  wheat  seed)  that  have  been 
soaking  in  water  for  about  twenty-four  hours,  between 
two  layers  of  cotton  or  cotton  cloth  (newspaper  or  blot¬ 
ting  paper  will  do).  Keep  the  covering  moist.  In  two 
or  three  days  roots  will  develop  and  will  be  covered  with 
a  thick  fuzz  of  root-hairs. 

Observe  the  extent  of  the  zone  of  root-hairs.  Note  also 
the  length  of  those  near  the  tip  of  the  rootlet  compared 
with  the  length  of  those  at  the  opposite  end  of  the  root- 
hair  zone. 

Select  a  seed  having  a  straight  root  and  put  it  on  a 
piece  of  moist  blotting  paper.  Mark  with  pencil  the  two 
extremes  of  the  root-hair  zone.  Put  away  for  several 
days,  being  careful  to  preserve  the  moisture  (cover  with 
inverted  tumbler)  and  also  being  careful  not  to  disturb 
the  position  of  the  root  with  reference  to  the  marks.  At  the 
end  of  three  to  five  days  (a  longer  time  if  temperature 
is  low)  the  root  will  have  increased  in  length  and  with  it 
the  extent  of  the  zone  of  root-hairs.  The  long  hairs  at 
the  mark  nearest  the  plant,  however,  will  show  signs  of 
collapse.  In  a  few  more  days  they  will  begin  to  shrivel 
up.  Thus  new  root-hairs  are  formed  at  the  tip  of  the 
root  while  the  old  ones  shrivel  up  and  disappear. 

The  root-hair  zone  is  always  about  the  same  length. 


New  hairs  are  formed  about  as  fast  as  the  old  ones  shrivel 
up,  so  that  the  tip  of  the  root  is  always  followed  by  the 
zone  of  root-hairs.  In  this  way  new  feeding  areas  are 
constantly  supplied  to  the  root.  (1,  p.  146.) 

IV.  How  the  Soil  Holds  the  Water. 

(Capillary  attraction  or  Capillarity.) 

Explanation : 

When  a  pencil  is  dipped  in  water  a  film  of  water  ad¬ 
heres  to  it.  This  attraction  of  a  solid  for  a  liquid  is  called 
capillary  attraction  or  capillarity. 

A  few  simple  experiments  will  make  clear  this  action. 

Demonstration : 

Set  two  square  or  rectangular  pieces  of  glass  in  a  pan 
of  water,  putting  the  two  vertical  edges  together  so  that 
the  pieces  of  glass  will  form  an  angle  of  five  or  ten 
degrees. 

Note  that  the  water  in  the  narrow  portion  of  the  angle 
rises  some  distance  above  the  level  of  the  water  in  the  pan. 
Here  the  capillary  attraction  is  greater  than  gravity,  for 
it  is  sufficient  to  draw  the  water  upward  for  a  short  dis¬ 
tance. 

The  same  may  be  shown  by  means  of  glass  tubes  of 
different  diameters.  The  water  in  the  tubes  having  the 
least  diameter  will  rise  to  the  greatest  height. 

A  lamp-wick  carrying  the  oil  upward  to  the  flame  is 
another  and  more  familiar  example. 

Application : 

Root-hairs  are  adapted  for  taking  up  water  that  adheres 
to  soil  particles.  (Fig.  1.)  This  fact  is  fundamental.  It 
must  be  kept  constantly  in  mind  in  all  considerations  of 
the  soil  where  the  growth  of  the  plant  is  concerned.  The 
soil  may  be  perfect  as  to  food  content  and  other  particu¬ 
lars,  but  if  the  water  does  not  exist  as  capillary  water,  i. 
e.  as  films  adhering  to  soil  particles,  the  root-hairs  are 
unable  to  do  their  work.  (1,  pp.  136-142;  12,  p.  6.) 


12 


V.  How  Water  Gets  Into  a  Root-Hair. 

Explanation : 

The  root-hair  may  be  considered  as  an  elongated  bag 
filled  with  a  liquid  denser  than  water.  When  two  liquids 
of  different  density  are  separated  by  a  membrane  the  less 
dense  liquid  tends  to  pass  through  the  membrane  more 
rapidly  than  the  more  dense  liquid.  This  produces  a 
greater  pressure  on  the  side  of  the  membrane  which  is 
in  contact  with  the  liquid  of  greater  density.  The  pres¬ 
sure  thus  exerted  is  known  as  osmotic  pressure.  The 
whole  phenomenon  is  called  osmosis.  (1,  pp.  147-153.) 

Demonstration  : 

Material:  A  wide-mouthed  bottle,  an  egg,  a  quarter- 
inch  glass  tube  six  inches  or  more  in  length,  a  piece  of 
candle  one-half  inch  long,  a  wire  somewhat  longer  than 
the  glass  tube. 

Preparation : 

Crack  the  large  end  of  the  egg  and  remove  part  of  the 
shell  being  careful  not  to  break  the  shell  membrane.  The 
shell  should  be  removed  from  an  area  of  about  one-half 
inch  in  diameter.  Remove  the  shell  from  the  small  end 
over  an  area  equal  to  diameter  of  glass  tube.  Bore  a  hole 
through  the  piece  of  candle  just  big  enough  to  receive  the 
glass  tube.  The  position  of  the  hole  should  correspond 
to  the  position  of  the  wick  in  the  candle.  Heat  the  end 
of  the  candle  and  stick  it  over  the  small  end  of  the  egg 
so  that  the  hole  in  the  candle  lies  just  over  the  hole  in 
the  shell.  With  a  hot  wire  melt  the  edges  of  the  candle 
so  as  to  fix  it  firmly  to  the  egg.  Place  the  glass  tube  in 
the  opening  of  the  candle  and  with  the  hot  wire  make 
the  joint  water-tight.  Break  the  egg  membrane  of  the 
small  end  of  the  egg  by  passing  the  wire  into  the  egg 
through  the  glass  tube. 

Now  fill  the  bottle  with  water  and  place  the  egg  on  the 
bottle  so  that  the  exposed  egg  membrane  of  the  large 
end  remains  below  the  surface  of  the  water. 

Action : 

In  about  an  hour  the  white  of  the  egg  will  be  seen  ris- 


13 


ing  in  the  glass  tube.  The  water  from  the  bottle  passes 
through  the  egg  membrane  and  pushes  the  egg  contents 
into  the  tube. 

VI.  Action  of  Water  in  Soil  Formation. 

Explanation : 

The  chief  factor  in  soil  formation  is  water.  The  erosive 
action  of  water  during  and  immediately  after  a  shower  is 
familiar  to  everyone.  On  a  large  scale  the  same  action  is 
involved  in  wearing  away  the  mountains  and  carrying  the 
material  to  lower  levels  where  it  is  deposited  in  the  form 
of  soil. 

It  is  important  in  teaching  this  subject  that  all  phases  of 
this  action,  which  extends  over  large  areas,  should  be 
brought  into  view  at  one  time.  The  child  sees  things  as 
wholes  and  it  is  difficult,  if  not  impossible,  for  him  to 
make  up  a  complete  picture  from  fragments. 

The  following  demonstration, which  may  be  prepared  and 
set  up  by  the  pupils  themselves,  is  intended  to  show  the 
whole  series  of  erosive  processes  at  work  in  one  picture. 
It  not  only  shows  the  actual  process  of  soil  making  but 
illustrates  many  important  facts  of  physical  geography. 

Apparatus : 

Three  boxes,  each  about  three  and  one-half  feet  long,  one 
foot  wide  and  six  inches  deep,  are  needed.  These  should 
be  hinged  together  in  a  series.  Strips  of  leather  the  width 
of  the  box  will  answer  very  well  for  hinges. 

Arrangement  of  apparatus : 

The  next  step  is  to  arrange  the  sections  so  that  they  will 
stand  at  different  levels.  The  first  one  should  be  level; 
the  second  inclined  about  fifteen  degrees ;  the  third  in¬ 
clined  about  thirty  degrees  ;  Strong  props  must  be  used 
to  hold  the  second  and  third  sections  in  place.  The  appa¬ 
ratus  as  set  up  is  shown  in  Fig.  2. 

The  sections  must  now  be  made  water  tight.  If  they  are 
set  up  out  of  doors  they  may  be  made  sufficiently  free 
from  leaks  by  stopping  the  openings  with  wet  clay.  Some 
provision  must  be  made  to  carry  the  water  from  the  upper 
section  to  the  second  section,  and  from  the  second  to  the 


14 


FIG.  2 

Apparatus  for  demonstrating  various  phases  of  erosion.  This  is  a 
picture  of  apparatus  as  set  up  in  the  country  model  school 
No.  1  of  the  Ohio  State  Normal  College. 


FIG.  3 

Apparatus  for  demonstrating  percolation  and  capillary  action 
of  different  soils. 


first.  Short  strips  of  oil  cloth  or  tin  extending  over  the 
joints  will  answer  this  purpose.  If  the  apparatus  is  to  be 
set  up  in  the  schoolhouse  more  care  must  be  taken  to  pre¬ 
vent  leakage.  The  best  way  will  be  to  line  the  entire 
length  of  the  trough  with  a  strip  of  oil  cloth  twelve  feet 
long  and  two  feet  wide.  At  the  lower  end  gather  up  the 
oil  cloth  so  as  to  form  an  outlet  to  carry  away  the  surplus 
water. 

After  the  apparatus  has  been  set  up  according  to  either  of 
the  above  methods  the  second  or  middle  section  should  be 
filled  with  sand,  and  the  upper  section  with  clay.  The 
clay  of  the  latter  may  be  made  to  vary  in  hardness  in  dif¬ 
ferent  places  by  mixing  it  with  sand.  The  lower  section 
should  be  empty. 

A  bucket  of  water  placed  above  the  highest  point  of  the 
upper  section  and  a  siphon  made  of  small  rubber  hose 
completes  the  apparatus. 

Action  of  water: 

Start  a  small  stream  of  water  from  the  siphon  and  al¬ 
low  it  to  trickle  down  the  entire  length  of  the  trough. 

“The  clay  mixture  in  the  upper  section  will  behave  in 
the  same  way  as  rock  (only  the  action  will  be  more  rapid), 
and  will  show  clearly  how  rock  is  sculptured  by  running 
water,  how  masses  of  it  become  detached  and  fall  ofif,  and 
how  as  these  are  carried  down  stream  they  lose  their 
sharp  edges.”  “In  the  second  section  we  will  see  land¬ 
slides,  terraces,  meanders,  oxbows,  bubbling  springs 
(where  an  obstacle  occurs),  and  all  other  features  of 
stream  action.  In  the  third  section  we  shall  see  alluvial 
fans  and  cones,  deltas,  beaches,  the  deposit  of  coarse  ma¬ 
terials  near  shore,  and  finer  materials  further  out  and  all 
the  features  of  lake  and  ocean  formations.”  *(1,  pp.  1-54; 
2,  pp.  47-60.) 

VII.  Soil  and  Subsoil. 

Explanation : 

In  a  climate  such  as  we  have  in  Ohio  the  surface  of 
the  earth  to  a  depth  of  from  six  to  twelve  inches  is  called 

*  Osterhont’s  "Experiments  with  Plants,”  pp.  110-lU. 


15 


soil.  Below  the  soil  is  the  subsoil.  According  to  King 
this  distinction  “grows  out  of  the  fact  that  oftentimes 
when  the  deeper  soil  is  brought  to  the  surface,  it  is  found 
unproductive  for  a  time,  and,  besides,  there  is  a  sharp  line 
of  demarkation  of  color  of  the  two  portions.”  (1,  p.  29.) 

Demonstration : 

The  sides  of  a  trench  or  steep  bank  of  a  road  will  fur¬ 
nish  a  good  illustration  of  soil  and  subsoil.  It  will  be 
necessary  to  scrape  off  an  inch  or  more  of  the  surface  so 
as  to  expose  the  soil  and  subsoil.  The  soil  may  be  easily 
recognized  by  its  dark  color.  All  below  is  the  subsoil. 

Where  no  such  situations  are  available  the  same  facts 
map  be  shown  by  digging  a  hole  or  trench  to  a  depth  of 
eighteen  inches  and  examining  its  sides  as  above  in¬ 
dicated. 

Collect  a  sample  of  the  soil  (a  large  handful)  for  use  in 
the  next  exercise. 

VIII.  What  Soil  Is  Made  Of. 

Explanation : 

Soil  is  a  mixture  of  sand  (rock  fragments),  fragments 
of  organic  matter  (animal  and  plant  refuse),  and  finer 
particles  known  as  silt  or  clay.  The  amounts  of  these 
vary  with  different  soils. 

Demonstration : 

(a)  Examine  a  small  amount  of  the  sample  taken  in 
previous  exercise.  Note  different  sizes,  shapes,  and  gen¬ 
eral  appearance  of  particles. 

(b)  Put  enough  of  the  soil  in  a  six-  or  eight-ounce 
bottle  to  fill  to  a  depth  of  one  and -one-half  inches.  Fill 
the  bottle  with  water,  cork  and  shake  vigorously  for  one 
minute.  Allow  the  mixture  to  settle  and  watch  the  pro¬ 
cess.  Note  the  kinds  of  particles  that  reach  the  bottom 
first,  what  next,  and  so  on.  Set  away  until  the  next  day. 
There  will  then  be  seen  several  layers  of  material  as  fol¬ 
lows  :  coarse  sand  on  bottom,  fine  sand  next,  silt  above 
this,  and  clay  on  top.  Floating  on  top  of  the  water  and 
perhaps  lying  on  top  of  the  clay  may  be  seen  some  dark 
particles.  These  are  organic  materials  or  humus. 

16 


IX.  Kinds  or  Types  of  Soil. 

Explanation : 

In  the  previous  exercise  attention  was  called  to  the  fact 
that  the  sample  of  soil  was  made  up  of  material  of  dif¬ 
ferent  kinds :  sand,  clay  and  humus.  As  all  soils  are  com¬ 
posed  essentially  of  these  three  materials  mixed  together 
in  various  proportion,  it  is  important  to  know  the  chief 
properties  of  each  type. 

Material : 

For  this  and  some  of  the  subsequent  exercises  a  supply 
of  each  type  of  soil  will  be  necessary.  About  one  gallon 
of  each  will  be  enough.  The  important  thing  is  that  each 
kind  of  soil  should  be  as  pure  as  possible.  Sand  may  be 
obtained  froui  the  sand  bars  of  any  brook  or  creek.  It 
should  be  washed  thoroughly  to  remove  the  clay  and  other 
impurities.  The  washing  is  done  by  stirring  the  sand  in 
a  bucket  of  water  and  then  pouring  off  the  muddy  water. 
Repeat  until  the  water  comes  off  clear. 

Clay  may  be  found  almost  pure  in  the  subsoil  in  many 
places.  The  steep  bank  of  a  “cut”  in  a  road  often  has  a 
streak  of  nearly  pure  clay  in  it.  The  clay  should  be  dried 
and  then  pulverized.  Putting  small  quantities  of  clay  at 
a  time  in  a  cloth  bag  and  pounding  it  is  the  most  con¬ 
venient  method. 

Humus  may  be  found  at  the  base  of  a  rotten  stump  or 
under  a  rotten  log.  Avoid  large  pieces.  The  fine  black 
material  is  most  desirable. 

Each  kind  of  soil  should  be  thoroughly  dried  and  kept 
in  a  dry  place. 

Demonstration : 

General  characters :  Examine  a  small  quantity  of  each 
type  and  compare  with  observations  of  Exercise  VIII. 
Behavior  toward  water:  (a)  Take  about  one  cubic  inch 
of  each  kind  of  soil  and  add  enough  water  to  make  a  plas¬ 
tic  mass.  Note  any  changes  in  appearances  or  behavior 
while  the  water  is  being  added.  Compare  the  effect  of 
water  on  the  three  kinds,  especially  as  to  changes  of  color 
and  resistance  to  handling  (i.  e.  relative  tendency  to  be¬ 
come  sticky). 


17 


(b)  Mould  each  kind  into  a  ball  and  put  away  to  dry. 
When  dry  note  the  effort  necessary  to  crush  or  break  up 
the  balls  of  each  kind. 

(c)  Fill  three  shallow  boxes  level  full  (baking  powder 
can-lids  will  do),  one  with  humus,  another  with  sand,  and 
the  third  with  clay.  Add  enough  water  to  thoroughly 
saturate  each.  Set  aside  until  the  water  evaporates,  leav¬ 
ing  the  soils  dry.  Note  how  long  it  takes  for  each  to  be¬ 
come  dry  and  also  the  amount  of  shrinkage  in  each. 

Application : 

This  exercise  shows  that  clay  is  responsible  for  many 
of  the  difficulties  of  handling  soil,  e.  g.  tenacity,  retention 
of  water,  baking,  cracking,  etc.  Many  of  the  problems  of 
soil  management  are  really  questions  of  how  to  deal  with 
clay.  When  a  soil  is  made  easier  to  work  its  texture  is 
said  to  be  improved.  Good  soil  texture  is  quite  as  im¬ 
portant  as  its  content  of  plant  food.  (1,  pp.  96-98;  9,  pp. 
11-13.) 

X.  How  Clay  May  be  Modified. 

Explanation : 

The  tenacity  of  clay  and  some  other  of  its  objectional 
features  are  due  mainly  to  the  small  size  of  its  particles. 
Any  improvement  of  clay  must  take  this  into  consider¬ 
ation.  The  purpose  of  this  exercise  is  to  show  some  ways 
of  separating  its  particles,  thereby  improving  its  texture. 

Demonstration : 

(a)  Effect  of  mixing  coarse  organic  material  on  the 
texture  of  clay. 

Take  four  samples  of  clay  (equal  quantities)  ;  mix  No. 
1  with  one-fourth  its  volume  of  coarse  humus,  No.  2  with 
one-third  its  volume,  No.  3  with  one-half  its  volume,  and 
keep  No.  4  as  a  control.  Add  enough  water  to  each  to 
form  a  stiff  plastic  mass.  Note  the  effect  of  the  humus  on 
the  tenacity  of  the  clay.  Mould  each  into  a  ball.  When 
it  has  hardened  and  become  dry,  test  hardness  and  resist¬ 
ance  by  breaking. 

(b)  Effect  of  lime  on  the  texture  of  clay. 

To  each  of  four  samples  of  clay  (weighing  about  100 

18 


grams)  add  the  following  amounts  by  weight  of  slacked 
lime:  No.  1,  1  per  cent;  No.  2,  5  per  cent;  No.  3,  10  per 
cent ;  No.  4,  none,  using  it  as  control. 

Mix  each  thoroughly  so  that  the  lime  may  be  evenly 
distributed,  and  add  just  enough  water  to  make  a  plastic 
mass.  Mould  each  into  a  ball  and  allow  to  dry  thor¬ 
oughly.  Test  the  resistance  of  each  by  dropping  upon  a 
brick  or  other  hard  surface.  Beginning  with  No.  3,  drop 
it  from  a  height  of  2,  then  4  inches,  and  so  on,  noting  the 
distance  through  which  it  must  fall  in  order  to  break.  Try 
Nos.  2,  1,  and  4  in  the  same  way.  The  distance  through 
which  the  balls  must  fall  in  order  to  break  will  indicate 
their  relative  tenacity.  Further  tests  may  be  made  by 
noting  the  ease  or  difficulty  in  breaking  or  crushing  the 
fragments  of  each  kind.  The  lime  has  changed  the  texture 
of  the  clay  and  made  it  less  tenacious. 

(c)  Action  of  lime  on  clay. 

The  action  of  lime  in  producing  the  above  modification 
of  clay  is  probably  due,  at  least  in  part,  to  flocculation, 
i.  e.  bringing  the  smaller  particles  together  to  form  com¬ 
pound  particles.  This  may  be  demonstrated  as  follows : 
Weigh  out  .2  grams  slacked  lime,  place  in  a  tumbler  and 
add  200  cubic  centimeters  of  water  (better  use  rain 
water.)  Put  the  same  amount  of  water  in  another  tumb¬ 
ler  for  control.  Now  add  to  both  tumblers  of  water  1 
gram  of  powdered  clay.  Stir  the  contents  of  both  and 
allow  to  settle.  In  the  one  to  which  the  lime  has  been 
added  flakes  or  masses  of  material  will  be  seen.  The  effect 
of  the  lime  has  been  to  flocculate  the  clay.  After  24  or 
48  hours,  when  the  particles  in  both  tumblers  have  set¬ 
tled,  examine  the  sediment.  The  sediment  in  the  tumbler 
to  which  the  lime  has  been  added  will  be  granular  while 
the  sediment  in  the  other  will  be  finely  divided. 

(d)  Effect  of  burning  on  clay. 

Put  a  piece  of  clay  in  a  hot  fire  and  burn  it  for  sev¬ 
eral  hours.  When  cool,  if  it  has  been  heated  enough,  it 
will  break  easily  and  show  very  different  properties  from 
unburnt  clay. 


19 


Application : 

The  experiments  performed  in  this  exercise  give  mean¬ 
ing  to  some  common  farm  practices.  The  use  of  coarse 
barnyard  refuse  on  soils  where  clay  predominates  not  only 
adds  fertility  (available  plant  food)  but  also  improves  the 
texture  of  the  soil  by  separating  the  fine  particles. 

Lime  not  only  acts  as  a  fertilizer  and  serves  to  neu¬ 
tralize  in  some  instances  the  acid  in  the  soil  but  helps 
make  the  clay  soil  easily  worked.  Lime  is  applied  at  the 
rate  of  about  twenty  bushels  to  the  acre  once  every  four 
or  five  years. 

When  wood  was  plentiful  it  was  the  practice  in  some 
places  to  improve  clay  soils  by  burning. 

It  must  be  understood  that  these  methods  are  only  ef¬ 
fective  when  the  soil  is  well  drained.  The  behavior  of 
clay  and  other  soils  toward  water  will  be  shown  in  the 
next  two  exercises.  (3,  p.  42;  7 ;  22;  23.) 

XI.  Flow  of  Water  Through  Different  Kinds  of  Soils. 

Explanation : 

There  is  a  great  difference  in  soils  in  their  behavior 
toward  the  water  that  falls  on  their  surfaces.  In  some 
soils  the  water  is  taken  up  so  readily  that  shortly  after  a 
shower  very  little  evidence  of  rain  is  noticed.  In  others, 
after  the  rain,  water  stands  in  puddles  and  it  is  some  time 
before  the  water  disappears  from  the  surface ;  even  then 
the  soil  is  soggy  or  muddy. 

How  the  character  of  the  soil  affects  its  power  to  take 
in  water  that  falls  on  its  surface,  may  be  shown  as 
follows : 

Apparatus : 

Four  student-lamp  chimneys,  a  rack  to  hold  them,  and 
a  pan  or  four  tumblers  to  catch  the  water  that  drains  from 
the  tubes.  (Instead  of  student-lamp  chimneys  ordinary 
lamp  chimneys  may  be  used.) 

Arrangement  of  Apparatus : 

Tie  pieces  of  cheese  cloth  over  the  small  ends  of  the 
chimneys.  Fill  them  nearly  full  respectively  of  dry  sand, 


20 


dry  clay,  dry  humus,  and  dry  garden  soil  (loam).  Place 
tubes  in  rack.  The  apparatus  as  set  up  is  shown  in  Fig.  3. 

Demonstration : 

Pour  water  into  the  upper  ends  of  the  tubes  until  it 
drips  from  the  lower  ends.  It  will  be  seen  that  the  humus 
and  sand  take  in  water  and  allow  it  to  flow  through  quite 
readily,  the  garden  soil  less  readily,  and  the  clay  quite 
slowly. 

Repeat  the  experiment,  using  dry  garden  soil  and  two 
tubes.  Pack  the  soil  tightly  in  one  and  leave  it  loose  in 
the  other.  The  water  will  of  course  penetrate  the  loose 
soil  much  more  readily  than  the  other. 

Application  : 

These  two  experiments  show  that  the  power  of  soil  to 
take  up  water  depends  upon  two  things :  the  size  of  the 
soil  particles,  and  the  compactness  of  the  soil.  Clay  and 
compact  soils  take  in  water  so  slowly  that  most  of  it  runs 
off  and  is  lost.  But  as  it  runs  off  it  carries  away  some 
surface  soil  leaving  the  surface  irregular. 

The  texture  of  such  soils  may  be  improved  by  keeping 
them  open  by  plowing  (fall  plowing)  and  tillage,  thus  in¬ 
creasing  their  water-holding  capacity.  The  texture  may 
be  further  improved  by  methods  indicated  in  the  last  ex¬ 
ercise  (coarse  barnyard  material,  lime).  (1,  pp.  157-162; 
2,  p.  68;  8,  p.  9.) 

XII.  How  Water  Moves  Upward  Through  Different  Soils. 

Explanation : 

Attention  has  already  been  called  to  the  phenomenon 
of  capillarity  or  capillary  attraction.  (Ex.  IV.)  Water 
exists  in  the  soil  chiefly  (a)  in  the  form  of  capillary  water 
i.  e.,  water  around  soil  particles  and  at  the  points  of  con¬ 
tact  between  the  particles ;  and  also  (b)  as  free  water,  i. 
e.,  water  that  completely  fills  all  the  spaces  between  the 
soil  particles.  In  the  upper  layers  of  the  soil  the  water 
exists  as  capillary  water ;  in  the  deeper  layers  it  exists 
as  free  water.  The  level  of  the  free  water  is  known  as 
the  water  table.  If  a  hole  be  made  in  the  ground,  as  for 
example  a  well,  the  water  will  rise  to  a  certain  level ;  this 


21 


level  is  the  water  table.  The  position  of  the  water  table 
varies  with  the  season,  being  influenced  by  rainfall,  at¬ 
mospheric  pressure,  etc.  (1,  pp.  163-183).  In  heavy  un¬ 
drained  soils,  especially  in  low  places,  the  water  table  is 
very  near  the  surface  of  the  ground.  Hence  the  im¬ 
portance  of  drainage. 

The  feeding  area  of  the  roots  is  in  the  region  of  the 
capillary  water.  If  the  water  table  is  near  the  surface  the 
feeding  area  will  be  shallow  and  the  plants  will  be  shal¬ 
low  rooted.  As  the  plant  removes  the  water  from  the 
feeding  area,  this  water  must  be  restored  by  capillary 
action  from  the  area  of  free  water  below.  It  will  thus  be 
seen  what  an  important  role  capillarity  plays  in  plant 
nutrition. 

Capillary  action  varies  in  different  soils  both  as  to 
rate  of  water  movement  and  also  as  to  the  height  to 
which  the  water  may  be  raised. 

Demonstration : 

Arrange  apparatus  as  in  Exercise  XII,  with  the  same 
apparatus  and  with  the  same  soils  (dry). 

In  the  experiment  have  the  lower  ends  of  the  tubes  ex¬ 
tending  about  one-half  inch  below  the  surface  of  water 
held  either  in  a  pan,  or  in  a  tumbler  for  each  tube. 

Note  the  rate  at  which  the  water  rises  in  each  tube,  and 
also  the  height  of  water  at  the  end  of  four  or  five  days. 
In  the  tube  of  sand  the  water  rises  rapidly  but  soon  stops, 
while  in  clay  it  rises  slowly  but  finally  reaches  the  top. 

The  sand  is  composed  of  large  particles,  while  the  clay 
is  composed  of  very  fine  particles.  The  results  of  this  ex¬ 
periment  would  indicate  that  the  power  of  soils  to  lift 
water  depends  upon  the  size  of  their  particles ;  in  other 
words,  upon  their  texture. 

Application : 

This  exercise  shows  the  disadvantages  of  sandy  soils, 
for  they  have  very  little  power  to  take  up  moisture  from 
below.  As  has  been  suggested,  this  is  because  of  the  large 
size  of  soil  particles  and  soil  spaces.  Such  soils  may  be 
improved  by  the  addition  of  fine  stable  manure  or  other 


22 


barnyard  refuse,  so  as  to  fill  up  the  soil  spaces  and  fur¬ 
nish  finer  particles.  Temporary  improvement  may  be 
made  by  compacting  the  soil,  e.  g.,  by  means  of  a  roller. 

This  exercise  also  shows  the  value  of  clay  soils  or  soils 
made  up  of  fine  particles.  The  property  of  clay  which 
enables  it  to  raise  water  through  considerable  distance 
makes  up,  in  a  measure,  for  some  of  the  undesirable  prop¬ 
erties  which  have  already  been  pointed  out  (Ex.  IX). 

We  have  seen  that  water  passes  through  clay  soils 
slowly  and  that  the  water  of  a  rain  is  apt  to  run  off  rather 
than  to  sink  into  the  ground.  The  value  of  drainage 
should  be  emphasized  in  this  connection. 

During  the  wet  weather  the  free  water  area  is  near  the 
surface  of  the  ground,  thereby  restricting  the  feeding  area 
of  the  plants  to  the  first  few  inches  of  the  soil,  and  in  low 
places  coming  so  near  the  surface  as  to  shut  off  this  area 
entirely.  The  latter  result  is  well  illustrated  in  nearly  ev¬ 
ery  locality  where  clay  soils  predominate.  In  the  low 
places  in  fields,  or  such  localities,  the  grain  is  frequently 
“drowned  out,”  or  if  not  “drowned  out,”  the  stalks  of 
grain  are  slender  and  unfruitful. 

On  the  other  hand,  during  hot,  dry  weather  the  water 
table  sinks  so  low  that  the  capillary  connection  with  the 
shallow  soil  area  where  the  roots  are  distributed  is  broken. 
Plants  then  suffer  from  insufficient  supply  of  water. 

The  remedy  for  these  two  undesirable  extremes  is 
drainage.  Good  drainage  means  the  control  of  the  level 
of  the  water  table.  If  during  the  early  wet  season  the 
water  table  is  some  distance  below  the  surface  of  the 
ground,  the  depth  of  the  feeding  area  of  the  roots  will  be 
increased.  When  the  dry  season  comes,  the  roots  will  be 
deep  enough  to  be  always  supplied  with  capillary  water. 

Drainage  is  also  important  in  its  influence  upon  soil 
ventilation  (Ex.  XVIII),  soil  temperature,  and  the  in¬ 
crease  of  available  plant  food.  With  good  drainage  and  the 
improvement  of  texture  by  means  of  manures  or  lime,  clay 
lands  are  very  valuable.  (1,  pp.  253-260;  2,  pp.  75-82;  8.) 
XIII.  Effect  of  Interrupting  the  Capillary  Current. 


23 


Explanation : 

The  effect  of  breaking  the  capillary  connection  between 
the  free  water  below  and  the  feeding  area  above  has  al¬ 
ready  been  noticed.  The  effect  may  be  shown  by  a  simple 
experiment. 

Demonstration : 

Fill  a  glass  tube  such  as  used  in  Exercises  XI  and  XII 
with  dry  garden  soil  to  a  depth  of  about  two  inches;  fill 
the  next  one  and  one-half  inches  of  space  with  dry  straw 
or  weeds ;  fill  the  remainder  of  the  tube  with  dry  garden 
soil.  Place  the  tube  with  its  end  below  the  surface  of  the 
water  as  in  Exercise  XII.  Note  the  rise  of  water  in  the 
tube.  When  the  level  of  the  straw  is  reached  the  water 
stops  rising.  The  large  particles  of  straw  break  the  capil¬ 
lary  connection. 

Application : 

Often  in  farm  practice  (bad  practice)  a  field  is  covered 
after  harvest  with  a  heavy  growth  of  grass  and  weeds.  In 
the  spring  these  are  plowed  under.  Later,  if  the  season 
is  dry,  the  crop  suffers  from  drouth ;  the  water  can  not 
get  past  the  layer  of  weeds  into  the  feeding  area  of  most 
of  the  roots,  just  as  illustrated  in  the  foregoing  experi¬ 
ment.  By  fall  plowing  this  condition  may,  in  part,  be 
avoided. 

XIV.  Amount  of  Water  Held  by  Different  Soils. 

Explanation : 

In  Exercise  XI  a  variation  may  have  been  noticed  in 
the  amount  of  water  necessary  to  be  added  to  the  differ¬ 
ent  tubes  before  it  began  to  drip  from  the  bottom  of  the 
tubes.  Some  required  more  water  than  others.  This  was 
due  to  the  difference  in  capacity  of  different  soils  for  hold¬ 
ing  water.  (1,  pp.  157-162.) 

The  amount  of  water  that  each  kind  of  soil  is  capable 
of  holding  may  be  determined  as  follows : 

Apparatus : 

Balances  and  weights,  tubes  and  rack  as  in  Exercise  XI. 

Demonstration : 

After  tying  cloth  over  the  bottoms  of  four  tubes,  weigh 


24 


each  tube  and  keep  a  record  of  the  weight.  The  tubes 
should  be  numbered  so  as  to  avoid  confusion.  Now  fill 
about  half  full,  tube  No.  1  with  dry  clay,  No.  2  with  dry 
humus,  No.  3  with  dry  sand,  No.  4  with  garden  soil. 
Weigh  each  one  and  record  the  weight  opposite  the 
weight  of  the  tube.  Add  water  to  each  tube  until  the  en¬ 
tire  soil  is  wet.  Cover  the  tops  and  allow  excess  water  to 
drain  off.  Weigh  each  tube  and  record  the  weight  with 
the  entry  made  of  the  previous  weights  of  that  tube.  With 
these  data  calculate  the  per  cent,  of  water  held  by  each 
kind  of  soil  as  follows :  Find  the  actual  weight  of  dry  soil 
by  subtracting  the  weight  of  the  tube  (first  weight)  from 
the  weight  of  tube  plus  dry  soil ;  next  find  the  weight  of 
water  by  subtracting  weight  of  tube  plus  dry  soil  from 
weight  of  tube  plus  wet  soil.  Determine  what  per  cent, 
the  weight  of  the  water  is  of  the  weight  of  dry  soil. 

It  will  be  found  that  the  humus  will  hold  a  much  larger 
per  cent,  of  water  than  any  of  the  other  soils,  while  the 
sand  will  hold  the  smallest  per  cent.  The  clay  and  the 
garden  soil  will  hold  more  than  the  sand. 

Application : 

The  value  of  adding  organic  matter  to  soils,  especially 
to  sandy  soils,  is  here  emphasized.  It  not  only  helps  to 
increase  the  capillary  power  of  the  sandy  soils,  and  add 
plant  food,  but  makes  them  hold  water  more  effectually. 

We  have  another  point  here  in  favor  of  clay  soils.  But 
this  point  is  sometimes  a  disadvantage,  e.  g.,  in  the  early 
spring.  Clay  soils  are  cold  because  they  contain  so  much 
water.  Deep  fall  plowing  and  early  shallow  plowing  in 
the  spring  may,  in  part,  remove  this  difficulty.  Fall  plow¬ 
ing  keeps  the  water  at  a  lower  level  and  early  shallow 
spring  plowing  hastens  the  evaporation  of  the  water. 
Sandy  soils  may  generally  be  planted  to  crops  much  ear¬ 
lier  in  the  spring  than  clay  soils. 

XV.  Evaporation  of  Moisture  from  Surface  of  Soils — Dew. 

Explanation : 

The  notion  that  dew  “falls”  still  obtains  in  the  minds 
of  many.  A  simple  experiment  will  show  where  part  of 


25 


the  moisture  which  we  call  dew  comes  from.  Part  of  the 
moisture  of  course  comes  from  plants,  for  they  are  con¬ 
stantly  giving  off  moisture  (transpiration)  but  a  good 
deal  of  it  comes  from  the  ground. 

Demonstration : 

Invert  a  tumbler  on  the  surface  of  moist  soil  and  leave 
it  over  night.  Drops  of  moisture  (dew)  will  be  seen  the 
next  morning  clinging  to  the  inside  surface  of  the  glass. 

Application : 

A  great  deal  of  moisture  is  constantly  being  evaporated 
from  the  soil.  At  night  it  is  condensed  on  cold  objects  in 
the  form  of  dew.  In  the  care  of  growing  crops,  it  is  im¬ 
portant  to  reduce  the  loss  of  water  through  evaporation 
to  a  minimum. 

XVI.  How  to  Keep  Moisture  in  the  Soil.  Soil  Mulch. 

Explanation : 

The  problem  of  having  a  large  supply  of  moisture  in 
the  soil  and  keeping  it  there,  except  when  used  by  the 
plant,  is  an  exceedingly  important  one.  How  to  keep 
moisture  in  the  soil  may  be  readily  shown. 

Apparatus : 

Two  one-quart  tin  cans,  balances,  and  weights. 

Demonstration : 

Fill  one  can  nearly  full  of  damp  garden  soil;  fill  the 
other  to  within  one  and  one-half  inches  of  the  top  with 
the  same  kind  of  soil  and  fill  the  rest  of  the  space  with 
dry  garden  soil. 

Weigh  each  can  thus  prepared  and  keep  record  of  the 
weights.  At  the  end  of  five  or  six  days  weigh  again.  The 
difference  between  the  two  weights  of  each  can  repre¬ 
sents  the  loss  of  water  through  evaporation.  Calculate 
the  percentage  of  loss  of  water  in  each.  The  loss  of 
water  in  the  second  can  will  be  very  slight  compared 
with  the  loss  in  the  first.  The  layer  of  dry  soil  on  the 
second  can  acts  as  a  blanket,  keeping  the  moisture  from 
evaporating.  This  covering  is  known  as  a  mulch.  (Fig.l.) 

Application : 

In  farm  practice  stirring  the  soil  forms  a  dry  top  layer 


26 


a  tumbler  of  puddled  clay  (clay  that  has  been  wet  and 
stirred  until  it  forms  a  pasty  mass).  Keep  the  contents 
of  both  tumblers  moist,  being  especially  careful  not  to 
allow  the  clay  to  get  dry  enough  to  crack. 

In  a  short  time  the  cutting  placed  in  the  sand  will  take 
and  prevents  the  loss  of  water.  It  also  prevents  the  soil 
from  baking.  Stirring  the  soil  is  especially  important  in 
times  of  drought.  (1,  pp.  276-285 ;  2,  pp.  69-71 ;  9,  21.) 

XVII.  Effect  of  Crust  on  Loss  of  Water. 

Explanation : 

The  soil  may  be  considered  as  a  sponge  holding  water 
for  the  plant’s  use.  The  effect  of  a  top  crust  on  the  loss 
of  water  from  the  lower  layers  of  soil  may  be  illustrated 
as  follows : 

Demonstration : 

Fill  a  sponge  with  water  and  support  a  dry  brick  above 
it  so  that  part  of  the  weight  of  the  brick  presses  against 
the  sponge.  The  brick  removes  the  water  from  the 
sponge  and  in  a  short  time  the  sponge  will  have  little 
water  left. 

Application : 

This  is  another  illustration  of  the  importance  of  stir¬ 
ring  the  top  layer  of  the  soil.  It  explains  why  the  suc¬ 
cessful  farmer  begins  his  cultivation  as  soon  after  a  rain 
as  possible. 

XVIII.  Air  in  Soils  a  Necessity  for  Plant  Growth. 

Explanation : 

Plants  as  well  as  animals  must  have  oxygen.  Part  of 
the  oxygeh  supply  of  the  plant  must  come  by  the  way  of 
the  roots ;  besides,  the  roots  themselves  need  oxygen.  A 
simple  experiment  will  illustrate  the  necessity  of  roots 
being  supplied  with  oxygen. 

Material : 

Cuttings  of  Wandering  Jew  (tradescantia  or  some  other 
plant  that  roots  easily  from  cuttings),  two  tumblers. 

Demonstration : 

Put  one  cutting  in  a  tumbler  of  wet  sand  and  another  in 


27 


root  and  in  a  few  weeks  it  will  show  a  decided  growth. 
The  cutting  placed  in  the  clay  will  probably  die  in  a  few 
weeks.  The  chief  difference  in  the  two  instances  is  in  the 
amount  of  oxygen. 

The  same  thing  may  be  shown  in  another  way.  Put  one 
cutting  in  fresh  well  water  and  another  in  water  that  has 
been  boiled  for  some  time  and  then  cooled.  Boiling  the 
water  drives  off  the  oxygen.  After  a  few  weeks  the  same 
difference  will  be  shown  as  between  the  cuttings  noted 
above. 

Application : 

We  have  here  an  explanation  of  why  in  low,  poorly 
drained  places  plants  are  “drowned  out.”  “Smothered 
out”  would  more  nearly  express  the  truth.  Plowing  and 
draining  the  soil  and,  to  a  certain  extent,  cultivation  help 
to  give  the  roots  oxygen.  When  the  texture  of  clay  is  im¬ 
proved  by  making  the  soil  spaces  larger,  not  only  is  a 
larger  feeding  area  secured  (an  area  containing  capillary 
water),  but  also  a  breathing  area  (soil  spaces  filled  with 
air  for  the  roots).  (1,  pp.  239-252;  2,  p.  66;  8;  9;  25.) 

XIX.  Amount  of  Air  Held  by  the  Soil. 

Explanation : 

We  have  seen  that  plants  require  water  in  the  form  of 
capillary  water  and  that  they  also  require  air  (oxygen). 
The  question  of  how  much  water  and  air  the  soil  should 
contain  may  be  answered  approximately  by  an  experi¬ 
ment. 

Demonstration : 

Fill  five  tumblers  with  garden  soil  and  plant  in  each 
five  wheat  grains.  Add  water  daily  as  follows:  to  No.  1, 
15cc. ;  to  No.  2,  10  cc. ;  to  No.  3,  5  cc. ;  to  No.  4,  3  cc. ;  to 
No.  5,  1  cc.  After  a  few  weeks  note  the  difference  in  size 
and  vigor  of  the  plants.  Select  the  tumbler  which  con¬ 
tains  the  plant  showing  the  best  growth.  In  this  the 
right  amount  of  water  has  been  added. 

Insert  a  small  tube  at  the  side  of  the  tumbler  so  that  it 
will  extend  to  the  bottom.  Pour  water  into  this  tube  by 
means  of  a  funnel  (keeping  account  of  the  amount  of 


2S 


water  added)  until  the  water  stands  level  with  the  sur¬ 
face  of  the  soil. 

The  water  added  to  the  soil  displaces  the  air,  therefore 
this  volume  of  water  is  equal  to  the  volume  of  air  in  the 
soil  spaces. 

Compare  this  with  the  total  volume  of  soil  (the  volume 
of  soil  may  be  found  by  removing  the  soil  from  the  tum¬ 
bler  and  filling  to  the  level  of  the  surface  of  the  soil  with 
water.  The  volume  of  water  added  in  cubic  centimeters 
represents  the  volume  of  the  soil).  Find  what  per  cent, 
the  volume  of  air  is  of  the  volume  of  the  soil.  In  general, 
a  soil  should  contain  water  equal  to  about  60  per  cent,  of 
its  water-holding  capacity.  This  leaves  40  per  cent,  (two- 
fifths)  of  the  soil  spaces  to  be  occupied  by  air.  See  how 
these  figures  compare  with  amount  calculated  in  above 
experiment. 

XX.  Fertility  of  the  Soil.  Plant  Food. 

Explanation : 

Thus  far  little  has  been  said  about  plant  food.  The 
plant  must  have  certain  substances  that  are  dissolved  in 
the  water  of  the  soil.  These  substances  that  are  taken 
into  the  plant  from  the  soil  are  known  as  available  plant 
food.  (2,  pp.  31-37;  4;  5;  6;  7.) 

Demonstration : 

Fill  two  cans  or  flower  pots  with  clean  sand  (sand  that 
has  been  washed  as  directed  in  Ex.  IX).  Plant  the  same 
number  (six)  of  grains  of  wheat  in  each.  Keep  one  wet 
or  moist  with  rain  water.  Keep  the  other  in  the  same  con¬ 
dition  as  to  moisture  with  rain  water  to  which  has  been 
added  plant  food  at  the  rate  of  two  compressed  tablets  to 
each  pint  of  water.  * 

*Note — Each  tablet  is  composed  of  :  Common  table  salt  (sodium  chloride)  2% 
grains  (.162  grams);  plaster  of  Paris— gypsum  (calcium  sulphate),  2%  grains  (.162  grams); 
Epsom  salts  (magnesium  sulphate,  2%  grains,  (.162 grams);  phosphate  of  lime,  nearly  the 
same  as  burned  bones  (calcium  phosphate),  2%  grains  (.162  grams;  East  India  saltpetre- 
nitre  (potassium  nitrate),  5  grains  (.325  grams);  compound  of  iron  and  chlorine  (ferric 
chloride),  nearly  1-10  grains. 


29 


For  awhile  there  will  be  no  difference  in  the  growth  of 
the  plants  in  the  two  cans.  In  the  course  of  two  or  three 
weeks,  when  the  food  stored  up  in  the  grains  is  exhausted, 
the  plants  in  the  first  can  will  cease  to  grow  or  grow  very 
little,  while  those  in  the  second  can  will  continue  to  grow 
vigorously.  The  substances  added  to  the  rain  water  used 
in  the  second  can  are  necessary  to  the  plant’s  growth. 
Such  substances  when  applied  to  soils  are  known  as  fer¬ 
tilizers. 


XXI.  Commercial  Fertilizers. 

Explanation : 

The  tablets  used  in  previous  exercise  contain  nearly 
all  the  substances  that  the  plant  derives  from  the  soil. 
All  but  three  of  these  (nitrogen,  phosphorus,  and  potas¬ 
sium)  are  generally  found  in  the  soil  in  sufficient  quanti¬ 
ties  for  the  need's  of  the  plant.  The  “essential  ingredi¬ 
ents”  of  a  fertilizer  are  substances  containing  these  ele¬ 
ments  ;  i.  e.  substances  which  supply  (a)  nitrogen  as  ni¬ 
trate  of  soda,  dried  blood,  hoof  meal,  etc.,  (b)  phosphorus 
in  form  of  phosphoric  acid  as  bone  meal  (raw  or  steamed), 
mineral  phosphates,  etc.,  (c)  potassium  in  form  of  potash 
as  wood  ashes,  kainite,  muriate  or  sulfate  of  potash,  etc. 

A  complete  fertilizer  is  one  that  contains  nitrogen, 
phosphoric  acid,  and  potash  in  proportions  supposed  to 
be  suited  to  the  needs  of  certain  crops.  Such  a  fertilizer 
is  made  by  mixing  substances  containing  the  basic  ingre¬ 
dients  so  as  to  give  the  desired  proportion  of  nitrogen, 
phosphoric  acid,  and  potash.  It  is  often  the  practice  to 
use  substances  rich  in  these  “essential  ingredients”  and 
dilute  the  mass  to  the  desired  strength  by  means  of  some 
inert  material  such  as  dry  earth.  Materials  used  in  this 
way  in  this  way  are  called  fillers.  A  2-8-4  fertilizer  means 
one  that  contains  2  per  cent,  nitrogen,  8  per  cent,  phos¬ 
phoric  acid,  and  4  per  cent,  potash.  If  the  percentages  of 
available  basic  ingredients  are  known  it  is  an  easy  mat¬ 
ter  to  calculate  the  value  of  a  fertilizer. 

Nitrate  of  soda  contains  15.8  per  cent,  nitrogen;  ni¬ 
trate  of  potash,  13  per  cent,  nitrogen  and  45  per  cent,  pot- 


30 


ash ;  sulfate  of  ammonia,  20.5  per  cent,  nitrogen ;  muri¬ 
ate  of  potash,  50  per  cent,  potash ;  acid  phosphate,  from 
14  to  16  per  cent,  phosphoric  acid. 

Problems : 

1.  How  many  pounds  of  nitrogen  are  in  a  ton  of 
nitrate  of  soda?  What  is  the  value  of  a  ton  of  nitrate  of 
soda  if  nitrogen  is  worth  14  cents  a  pound? 

2.  Suppose  an  equivalent  of  200  pounds  per  acre  of  a 
5-8-2  fertilizer  is  to  be  applied  to  20  acres,  determine : 

(a)  How  much  of  each  of  the  following  fertilizer  in¬ 
gredients  would  be  required : 

1.  Nitrate  of  soda,  96  per  cent,  pure,  at  $50  a  ton. 

2.  Acid  phosphate  containing  14  per  cent,  available 
phosphoric  acid,  at  $15  a  ton. 

3.  Potassium  chloride  (muriate  of  potash),  80  per 
cent,  pure,  at  $40  a  ton. 

(b)  What  would  be  the  cost  per  ton  of  a  5-8-2  fer¬ 
tilizer  based  upon  cost  of  ingredients  as  calculated 
in  (a) ? 

(c)  How  much  less  would  the  mixture  weigh  made 
from  above  separate  fertilizers  than  if  a  5-8-2  fertilizer 
were  purchased?  In  other  words,  how  many  pounds 
of  filler  must  be  added  per  ton  in  order  that  the  5-8-2 

proportion  be  maintained?  * 

Application : 

These  problems  illustrate  a  practical  application  of 
arithmetic  in  estimating  the  value  of  a  commercial  fer¬ 
tilizer.  One  should  remember  that  the  lowest  stated 
amount  of  available  nitrogen,  phosphoric  acid,  and  pot¬ 
ash  are  the  only  materials  to  be  considered  in  a  guaran¬ 
teed  analysis  although  other  statements  frequently  occur 
in  the  printed  analysis  of  a  fertilizer. 

State  Experiment  Stations  furnish  bulletins  giving 
analysis  of  various  commercial  fertilizers  on  the  market. 
By  means  of  these  bulletins,  and  by  knowing  the  market 


*  From  Circular  77,  Office  of  Experiment  Stations,  U.  S.  Department  of  Ag¬ 
riculture. 


31 


price  of  the  “essential  ingredients”  the  actual  value  of 
any  fertilizer  may  be  readily  estimated.  (2,  pp.  185-253.) 

XXII.  How  to  Know  What  Kind  of  Plant  Food  the  Soil 

Needs. 

Explanation : 

This  is  a  hard  question  to  answer  definitely.  Many 
times  certain  fertilizers  are  added  to  soils  but  produce  no 
results.  They  do  not  fulfill  the  needs  of  the  crop.  It  is 
important,  if  possible,  to  know  the  needs  of  the  soil  with 
respect  to  the  intended  crop  before  it  is  planted.  To  make 
such  a  test  as  this  is  a  problem  that  has  been  much 
studied.  A  rough  or  approximate  test  has  been  suggested 
by  the  U.  S.  Bureau  of  Soils.  Directions  for  making  this 
test  will  be  found  in  26.  Directions  for  making  the  test 
in  a  different  way  may  be  found  in  10. 

Boys  of  the  seventh  or  eighth  grade  should  be  able 
to  carry  out  the  instructions  of  these  references.  .  The 
chemicals  needed  may  be  obtained  at  a  drug  store  or 
where  fertilizers  are  for  sale. 

The  practical  value  of  such  tests  is  fully  described  in 
23  and  24. 

Reference  Books  and  Pamphlets. 

These  references  should  be  in  the  school  library  for  use 
in  connection  with  the  work  outlined  in  this  bulletin.  The 
prices  of  books  are  given  so  that  they  may  be  obtained  direct¬ 
ly  from  the  publishers. 

The  pamphlets  are  all  free  and  may  be  obtained  by  pos¬ 
tal  cards  to  the  addresses  indicated  below  *  and  giving  the 
number  of  the  publications  wanted.  In  the  case  of  U.  S.  Gov¬ 
ernment  publications  give  also  the  class  to  which  they  be¬ 
long  (Farmers’  Bulletin  No.  77;  Office  of  Exp.  Sta.,  Cir.  No. 


52,  etc.) 

1.  The  Soil.  By  F.  H.  King. 

New  York:  Macmillan  Co.,  pp.  303 . $1.50 

2.  First  Principles  of  Soil  Fertility.  By  Alfred  Vivian. 

New  York:  Orange  Judd  Co.,  pp.  265 . 90 


32 


3.  The  First  Book  of  Farming.  By  C.  L.  Goodrich. 

New  York:  Doubleday,  Page  &  Co.,  pp.  250..  1.00 

4.  The  Value  of  Barnyard  Manure.  Bulletin  No.  134. 

5.  The  Maintenance  of  Fertility.  Bulletin  No.  141. 

6.  Ohio  Soil  Studies.  Bulletin  No.  150. 

7.  Maintenance  of  Fertility.  Bulletins  Nos.  159,  167,  168. 

8.  Soil  and  Drainage.  Vol.  1,  No.  2. 

9.  An  Elementary  Story  of  the  Soil.  Vol.  1,  No.  4. 

10.  Testing  Soils.  Vol.  1,  No.  6. 

11.  Conditions  Necessary  for  Plants  to  Grow  Well.  Vol.  1, 

No.  8. 

12.  Tillage  and  Cultivation.  Vol.  1,  No.  9. 

13.  The  Formation  of  the  Soil.  Vol.  2,  No.  5. 

14.  Drainage.  Vol.  3,  No.  1. 

15.  Preparation  of  the  Seed  Bed.  Vol.  4,  No.  1. 

16.  The  Roots  of  Plants.  Bulletin  No.  127. 

17.  A  Few  Good  Books  and  Bulletins  on  Nature  Study, 

School  Gardening,  and  Elementary  Agriculture  for 
Common  Schools.  Office  of  Experiment  Stations. 
Cir.  No.  52. 

18.  Education  for  Country  Eife.  Office  of  Experiment  Sta¬ 

tions,  Cir.  No.  84. 

19.  The  Use  of  Illustrative  Material  in  Teaching  Agriculture 

in  Rural  Schools.  1905  Year  Book  Reprint,  No.  382. 

20.  Exercises  in  Elementary  Agriculture.  Office  of  Experi¬ 

ment  Stations,  Bulletin  No.  186. 

21.  Simple  Exercises  Illustrating  Some  Applications  of 

Chemistry  to  Agriculture.  Office  of  Experiment 
Stations,  Bulletin  No.  195. 

22.  The  Liming  of  Soils.  Farmers’  Bulletin,  No.  77. 

23.  Renovation  of  Worn-out  Soils.  Farmers’  Bulletin, 

No.  245. 

24.  Soil  Fertility.  Farmers’  Bulletin,  No.  257. 

25.  Management  of  Soils  to  Conserve  Moisture.  Farmers’ 

Bulletin,  No.  266. 

26.  The  Wire-basket  Method  for  Determining  the  Manurial 

Requirements  of  Soils.  Bureau  of  Soils,  Cir.  No.  18. 

♦Note— Nos,  4,  5,  6,  7;  Ohio  Agricultural  Experiment  Station,  Wooster,  Ohio. 

Nos.  8,  9,  10,  11,  12,  13,  14, 15;  Extension  Department,  Agricultural  College,  Ohio  State 
University,  Columbus,  Ohio. 

No.  16;  Kansas  Agricultural  Experiment  Station,  Manhattan,  Kan. 

Nos.  17,  18,  19,  20,  21,  22,  23,  24,  25,  26,  U.  S.  Department  of  Agriculture,  Washington, 
D.  C.  (Address  Sec’y  of  Agriculture.) 


33 


List  of  Apparatus  Required  for  Work  Outlined. 


1.  Balances,  Harvard  Trip  Scales  . $4.15 

2.  Weights  (iron,  1  kilo,  to  5  grams)  .  1.05 

3.  Funnel,  small,  glass  . 10 

4.  Graduate,  50  ccm . 55 

5.  Glass  tubing,  assorted  sizes,  y2  lb . 25 

6.  Rubber  tubing,  in.  3  ft . . 30 

7.  Wide-mouthed  bottles,  with  corks,  6  oz.,  ]/2  doz...  .20 

8.  Sponge  . 10 

9.  Candle  . 03 

10.  Tumblers,  common  glass,  y2  doz . 15 

11.  Student-lamp  chimneys  . 50 

12.  Oil  cloth,  4  yds . 80 

13.  Lumber  for  boxes  (for  Ex.  VI.)  .  1.00 

14.  Compressed  plant-food  tablets . 10 

15.  Slacked  lime,  small  quantity  . 


16.  Tin  cans  (tomato  or  fruit  cans  with  tops  melted  off) 

17.  Rack  for  tubes,  Ex.  XI.  (to  be  made  by  pupils.  . . . 

18.  Dry  goods  boxes  to  make  case  for  protecting  plants  1.00 

Total  . $10.28 

Substituting  spring  balances,  costing  25  cents,  for 

1  and  2,  deduct  .  4.95 


$5 . 33 

Note — Nos.  1,  2,  3.  4,  5,  may  be  obtained  from  the  Columbia  School  Supply  Co,  In¬ 
dianapolis,  Ind.,  or  from  any  firm  dealing  in  laboratory  supplies;  Nos.  6,  7  and  8,  at  any 
drug  store;  Nos.  9,  10,  11  and  12,  at  any  general  merchandise  store;  Nos,  13  and  18,  might 
be  donated  to  the  school;  No.  14,  enclose  10  cents  for  box  of  “compressed  plant  food  tab¬ 
lets,”  and  address  Edward  F.  Bigelow,  Sound  Beach,  Conn. 

The  items  of  greatest  expense  are  1  and  2,  but  they  are  so  important  in  a  school 
equipment  that  they  should  be  obtained  if  possible. 


34 


Provision  for  Keeping  Plants  Alive  During  Cold  Weather. 

Where  the  temperature  of  the  building  falls  below  freez¬ 
ing  at  night  or  during  the  interval  between  Friday  and 
Monday,  some  provision  must  be  made  for  keeping  plants 
alive.  The  few  plants  that  are  needed  in  connection  with  some 
of  the  foregoing  exercises  may  be  protected  from  cold  by  use 
of  a  double-walled  case.  The  walls,  including  the  bottom, 
should  be  from  six  to  eight  inches  apart,  and  the  spaces  filled 
tightly  with  packing  material  (straw,  saw-dust,  or  excelsior). 
Such  a  case  may  be  made  by  using  a  large  dry  goods  box 
about  four  feet  square  for  the  outer  walls,  and  a  smaller  box 
about  two  and  one-half  or  three  feet  square  for  the  inner 
walls.  In  putting  them  together  and  in  filling  the  spaces  with 
packing  material  the  edges  of  the  open  ends  of  the  boxes 
should  be  parallel  (on  a  line).  The  spaces  should  be  packed 
even  with  the  open  ends  of  the  boxes  and  then  covered  with 
boards.  This  completes  an  open  case  with  walls  and  bottom 
six  or  more  inches  thick. 

A  double  door  or  lid  must  be  made  to  close  the  opening. 
It  may  be  made  by  constructing  a  frame  six  or  seven  inches 
wide  that  will  just  fit  the  opening.  One  side  of  the  frame  is 
then  covered  with  thin  boards.  The  box  thus  formed  is  to 
be  filled  with  packing,  and  enclosed  by  nailing  boards  over  the 
open  side. 

It  is  convenient  to  have  these  boards  extend  about  two 
inches  around  the  margin  of  the  box.  In  order  to  make  the 
lid  fit  tightly,  its  edges  should  be  covered  with  thick  cloth. 
This  is  very  important,  for  a  very  small  crack  will  allow  the 
cold  to  enter.  A  couple  of  leather  handles  attached  to  the 
outside  completes  the  lid. 

If  the  box  is  properly  constructed  with  a  thick,  tightly 
fitting  lid,  plants  may  be  kept  alive  for  several  days,  even  in 
very  cold  weather.  The  plants  must  be  put  in  and  the  box 
closed  while  the  air  in  the  room  is  warm  (the  warmer  the 
better).  The  thick  walls  of  the  box  will  then  retain  a  suffi¬ 
cient  amount  of  this  heat  to  keep  the  temperature  above  freez¬ 
ing.  During  the  day-time  while  the  school-room  is  warm  the 
plants  must  be  taken  out  and  kept  in  sunlight. 

v  By  placing  the  box  with  the  opening  at  the  side,  the  top 
map"  be  used  as  a  laboratory  table. 


PUBLICATIONS  OF  OHIO  STATE  NORMAL  COL¬ 
LEGE  OF  MIAMI  UNIVERSITY. 


These  publications  form  a  series  of  teachers’  bulletins  is¬ 
sued  by  the  Ohio  State  Normal  College  of  Miami  University 
for  the  benefit  of  the  teachers  of  the  State,  and  in  the  inter¬ 
est  of  public  education. 

All  requests  from  teachers  desiring  these  bulletins,  or  in¬ 
formation  regarding  educational  movements,  will  receive 
prompt  attention.  Address  Teachers’  Aid  Bureau,  Ohio  State 
Normal  College,  Oxford,  Ohio. 

1.  Nature-Study,  by  George  W.  Hoke,  12  pp.,  3  figs.,  Octo¬ 
ber,  1903.  Outline  for  study  of  trees,  weeds,  insects, 
birds,  etc.,  with  list  of  books  for  reference. 

2.  Geography,  by  George  W.  Hoke,  15  pp.,  1  plate,  May, 
1904.  Treats  of  principles  of  Geography,  and  Regional 
Geography,  with  suggestive  exercises  for  class  work. 

3.  Evolution  of  Public  Education  in  Ohio,  (A)  Legislation, 
by  Harvey  C.  Minnich,  20  pp.,  2  maps,  March,  1907.  A 
historical  account  of  school  legislation. 

4.  The  Manual  Arts,  by  F.  C.  Whitcomb,  15  pp.,  April,  1907. 
Suggestions  as  to  course  of  study  and  equipment,  with 
special  reference  to  needs  of  small  school  systems. 

5.  The  Soil  and  Its  Relation  to  Plants,  by  B.  M.  Davis,  35 
pp.,  6  figs.,  May,  1907.  Subject  presented  by  means  of 
simple  experiments. 

6.  Evolution  of  Public  Education  in  Ohio,  (B)  Certifica¬ 
tion,  by  Harvey  C.  Minnich,  23  pp.,  November,  1907. 
Continuation  of  No.  3. 

7.  Experimental  Studies  of  Plant  Growth,  by  B.  M.  Davis, 
31  pp.,  17  figs.,  May,  1908.  Forty-two  experiments  suit¬ 
able  for  small  high  schools. 

8.  Stories  for  the  Elementary  Grades,  by  Anna  E.  Logan, 
20  pp.,  September,  1908.  Arranged  with  special  refer¬ 
ence  to  the  needs  of  teachers,  introducing,  or  increasing 
story-telling  work  in  their  schools. 

9.  Arithmetic  in  the  Grades,  by  T.  L.  Feeney,  19  pp.,  Janu¬ 
ary,  1909.  General  discussion  followed  by  outline  of 
course  of  study. 

10.  English  in  the  Grades,  by  Frances  Gibson  Richard.  2>j 

pp.,  March,  1909.  Detailed  outline  including  titles  A 
selections  for  all  the  grades.  ,  ; 

11.  The  Soil  and  Its  Relation  to  Plants,  by  B.  M.  Davisy  3> 
pp.,  December,  1909.  Revised  edition  of  No.  5. 


36 


